Haemostat materials for use in the treatment of wounds or other openings at a physiological target site in or on human or animal body which are exuding blood and/or other bodily fluids have been known for some time. These haemostat materials act to absorb the blood and/or other bodily fluids, and also stem the flow of them from the body. Haemostat materials for such use are described in, for example, WO 2009/130485 and WO 2012/123728 to MedTrade Products Ltd., and are commercially available under the trade name Celox®.
One material that is commonly employed as a haemostat material is chitosan. Chitosan is a known haemostat material, and is a derivative of solid waste from shellfish processing and can be extracted from fungus culture. It is a cationic polymeric material that is insoluble in water.
There are many different types of chitosan that may be used as a haemostat material, with different haemostatic properties. The different types of chitosan may have different molecular weights, different degrees of deacetylation, different arrangements of the two monomers, different chiral forms, or they may be derived from different species or sources (and fungi), or may have been treated differently during manufacture. Each of these differences can impact upon the levels of solubility and polymer structures of the respective chitosan materials, and therefore provide different chitosan materials having differing haemostatic properties.
The control of bleeding is essential and critical during surgical procedures. The aim of controlling bleeding is essentially to minimize blood loss, which in turn may shorten the duration of the surgery in the operating room and ultimately lead to a reduction in post-surgical complications. Haemostat compositions are of significant use during surgery for this purpose, but must always be removed at the end of the procedure when the incision in the patient is closed up.
However, there remains a need for a haemostat composition that is able to be used safely within the human or animal body, after as well as during surgical procedures, and which can subsequently be allowed to remain in the body to promote healing post-surgery. It would be beneficial to have a haemostat composition that is safely absorbable within the body within a defined period of time, as this would eliminate the need to remove the product prior to closure of the patient, and would allow the haemostat composition to remain in the body to reduce the likelihood for re-bleeding post-surgery. Further, such an absorbable and degradable haemostat composition would negate the need for further surgery to remove the haemostat. Such a degradable haemostat composition for post-surgical use has never previously been developed.